Question

When I try to import something inside application:

from app_name.models import something 

i have import error,
I must do it:

from models import something

This problem occurs only in one of many apps in project. What should I change?

Answer 1

It’s either what @Skirmantas suggested, that app_name is not on the PYTHONPATH, or you have a package clash, where some other app_name is preceding your app_name on the PYTHONPATH.

My hunch is that it’s probably the latter, that you have an app that has the same package name as some other third-party app your using; I once had two top-level registration packages on my PYTHONPATH.

If you take my failure with the registration app as an example, you’ll usually package your project something like this:

myproject/
    myproject/
         registration/
             __init__.py
             models.py
         __init__.py
         settings.py
         urls.py
    setup.py

It’s a community guideline that apps should be packaged to be “plug-and-play” compatible. They should be a top-level package and should be able to refer to intra-package resources through an absolute path like @Yuji suggested. If you like to ship and package your apps with your project, that means that in addition to /myproject, /myproject/myproject is also be on the PYTHONPATH. It’s even enforced in some cases.

As I said, it’s just a hunch that you have clashing package names. If that’s the case, then after this long-winded post you should understand that the only option you have is to rename your package to something more unique, but I would never have the heart to just spill it out immediately to someone. It’s due to the sad truth that I’ve never found a more suitable name to replace registration.